The lubricant in a dry sump, two-stroke engine recedes from the moving parts of the engine and into the crankcase after the engine has been disabled. The rate at which any lubricating film deposited on the moving parts recedes from the parts and into the crankcase is a function of the amount of time the engine has been disabled. After a period of time, the film is substantially depleted from the moving parts.
Upon engine restart, the degree of film remaining on the moving parts determines the degree of protection of the moving parts against engine friction for a period of time until appropriate circulation of the oil settled into the crankcase can re-establish a protective film on the moving parts. Significant wear of the moving parts may occur during the period of time until such circulation occurs.
It is generally known to introduce lubricant to a two-stroke engine at a rate proportional to certain engine operating conditions, such as a commanded fueling rate to the engine. Such conventional approaches do not account for the heightened potential for engine wear at startup, leaving the engine exposed to a significant wear condition.
Accordingly, what is needed is an approach to lubrication of a dry sump two-stroke engine that addresses the potential for significant engine wear associated with certain engine startup conditions.